1. Field of the Invention
The present invention relates to displays used in electronic devices such as laptop computers and avionics and marine equipment. More particularly, the invention relates to a computer program and method for controlling the brightness of a display by proportionally modifying the luminosity of each pixel in the display.
2. Description of the Prior Art
Thin-film transistor (TFT) liquid crystal displays (LCDs) and other types of displays are commonly used in a variety of electronic devices, including laptop computers, avionics and marine equipment, and global positioning satellite (GPS) receivers. Such displays typically have back lights that may be adjusted to brighten the displays when used in bright light and dim the displays when used in low light.
Adjusting the brightness of a back light to brighten or dim a display works well in most applications; however, back lights can only be dimmed so much before they effectively turn off entirely. Thus, once the lowest threshold of a back light has been reached, its display cannot be effectively dimmed any further. Those skilled in the art will appreciate that it is often desirable to dim a display beyond the lowest threshold of its back light in some environments such as in the cockpit of an aircraft or boat at night.
Accordingly, there is a need for an improved display and method of operation that overcomes the limitations of the prior art.
The present invention solves the above-described problems and provides a distinct advance in the art of display technology. More particularly, the present invention provides a computer program, method, and device for controlling the brightness of a display by proportionally varying the charge delivered to each pixel in the display after the back light for the display has been dimmed to its approximate lowest level.
One embodiment of the display of the present invention broadly includes a back light; a display module having an array of pixels that may be individually controlled to selectively block or pass light from the back light to create a desired image; a user interface for selectively adjusting the brightness of the back light to vary the amount of light passing through the pixels to control the brightness of the image; and a controller for proportionally adjusting the luminosity of the pixels to further control the amount of light passing through the pixels to control the brightness of the image. Thus, the controller and the user interface cooperate for dimming the display module in two ways: first by dimming the back light until it reaches its lowest threshold, and then by proportionally reducing the luminosity of the display module pixels to further limit the amount of light that passes through the pixels.
The preferred display also includes a color filter to render light passing through each of the pixels either red, green, or blue. These colors are combined and varied in intensity to create different color combinations. To dim the brightness of the display beyond the threshold of the back light, the controller proportionally lowers the values of the red, green, and blue components of all colors on the display. This dims the display while still maintaining the relative color gradations of the display.
By constructing a display as described herein, numerous advantages are realized. For example, by proportionally adjusting the luminosity of the pixels of the display, the brightness of the display can be further dimmed once the back light has been dimmed to its approximate lowest level. This allows the brightness of the display to be dimmed beyond the lowest threshold of the back light to accommodate for special operating environments such as in an aircraft or boat cockpit at night.
These and other important aspects of the present invention are described more fully in the detailed description below.